#B03C0E

CSS

:root {
  --rust: #b03c0e;
  --rust-rgb: 176 60 14;
  --rust-oklch: oklch(0.517 0.16 38.5);
}

.element {
  color: var(--rust);
  background-color: hsl(17 85% 37%);
  border-color: oklch(0.517 0.16 38.5);
}

Tailwind CSS v4

@theme {
  --color-rust: #b03c0e;
  --color-rust-50: #ffe7d3;
  --color-rust-100: #ffd7c0;
  --color-rust-200: #ffbda0;
  --color-rust-300: #fc9a77;
  --color-rust-400: #ec7953;
  --color-rust-500: #da5628;
  --color-rust-600: #b84a24;
  --color-rust-700: #943b1d;
  --color-rust-800: #6f2915;
  --color-rust-900: #4e1c0e;
  --color-rust-950: #330b02;
}

SCSS

$rust: #b03c0e;
$rust-rgb: 176, 60, 14;
$rust-light: mix(#fff, $rust, 20%);
$rust-dark: mix(#000, $rust, 20%);

.element {
  color: $rust;
  box-shadow: 0 0 0 2px rgba($rust, 0.35);
}